張威尊 發表：
電力不夠, 儀表版訊息會亂跳出來... 大 ...
晶片改裝導讀-2
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Since having the right air/fuel (A/F) ratio will be the difference between making power and
grenading your engine--though modern EMSs will almost never let an engine damage itself
--tuners spend a lot of time getting it just right.
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空燃比 (A/F ratio) 通常直接影響跟引擎動力與油耗表現, 晶片開發需要花大量的時間, 去
找出最合適的空燃比.
Too lean and the engine pings, too rich and you lose power. All tuners rely on a wide-band
UEGO A/F meter for fuel tuning. Wide-band A/F meters provide rapid and precise measurement
of A/F ratio by sampling the exhaust gas composition as it exits the engine.
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供油太少, 引擎會爆震, 供油太濃, 車反而不會跑...
For the naturally aspirated M5, Powerchip claims to target an A/F ratio of 12.9:1 at WOT
for optimal power before detonation becomes a problem. I keep mentioning WOT because
when the throttle is held open, the engine becomes loaded and the ECU will think the driver
is asking for power, not economy. The ECU will kick into a power enrichment (PE) mode
which uses a separate map providing a richer mixture and not bound by closed loop operation
or long term adaptive corrections (see below).
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以 PowerChip 替 M5 開發的晶片為例, 空燃比希望在全油門時, 是可以維持在 12.9, 這是
在保護引擎不爆震的前提下, 獲取最大動力的折衷設定...
在這裡不斷提到 WOT (全油門) 操作, 那是因為, 一套晶片程式, 裡面通常含有兩種模式,
一種為 "Close Loop 模式", 一種為 "Power Enrichment 模式"... 兩套模式的切換, 就在於
是不是全油門的操作...
當你全油門的時候, 晶片程式會認為你需要的是性能, 而不是經濟... 他就會切入 PE 模式,
以較濃的供油曲線來壓榨動力, 一般而言, Close Loop 模式的空燃比是 14.7:1, PE 模式則是
在 12.5 上下...
